HF Propagation

Radio and TV signals aren't always limited to traveling line of sight distances. On HF this is commonly caused by refraction (bending) of the signal at the upper layers of the atmosphere known as the ionosphere. On frequencies higher than this, while solar activity plays a role, Earth based weather events are the most common cause of propagation. These links explore several sites, and software, that can be used to help predict how a HF signal will propagate. For propagation topics above 30 Mhz, please see our DXing Above 30 Mhz article.

Links and Online Maps

Links

• ARRL Propagation pages
• AC6V Propagation Links
• EHam Propagation Links
• HF-Start
• Simon's World Map

Online Maps

• Earth View great for seeing Greyline
  • Earth View (Mercator projection)
  • Earth view (from above)
• Near-Real-Time MUF Map
• Hourly Propagation Maps via HFPack
• PropNet Communication Circuit Quality Report

Software

• Daylight Clock applet Greyline Display and Clock for the Logitech SqueezeBox series Wifi players.
• Proplab Pro
• VOACap
  • VOACap for ham radio
• VOAProp
• W6ELProp propagation prediction software

Technical

• ARRL - Sun, Earth and the ionosphere
• Australian Space Weather Services
• DX QSL Net-Propagation
• Global Ionosphere Radio Observatory
• HFRadio.org Propagation, Space Weather and Sunspot Cycle Resource Center
• HF Underground - Propagation Data and Tools
• International Space Environment Service
• NASA Stereo Website (Goddard Space Flight Center)
• NOAA Space Weather Prediction Center
  • HF Radio Communications
  • Radio Communications Dashboard
  • Space Weather Enthusiasts Dashboard
  • NOAA Radio Communications Dashboard
  • NOAA Real Time Solar Wind
• Solar Activity and HF Propagation Note: PDF file from QRPARCI
• Solar Dynamics Observatory
• SolarHam
• Solar and Heliospheric Observoatory (SOHO)
• Solar Influences Data Analysis Center
• SolarMonitor.org
• Solar Terrestrial Dispatch
• Spaceweather.com
• SpaceWeather Canada
• Topband Propagation
• Tromso (Norway) Geophysical Observatory
• WM7D Solar Research Page
• Working the Grey Line
• Usable HF Frequencies - Amateur Radio